1. Technical Field
The present invention relates to an aircraft and a control method for the aircraft.
2. Description of the Related Art
In an electronic manipulation system generally referred to as a fly-by-wire (hereinafter referred to as “FBW”) system, among aircraft manipulation systems, manipulation characteristics are improved by performing control of giving FBW control law commands, such as an attitude command control causing the amount of change in the attitude of an aircraft to correspond to a manipulation amount for a control stick and a speed command control causing the amount of change in speed to correspond to the manipulation amount for the control stick, to an actuator for driving a steering mechanism.
As a system for realizing control similar to the control of the FBW system by a mechanical manipulation system in which the control stick and the steering mechanism are mechanically connected with a series actuator (SAS (stability augmentation system) actuator) for mechanical linkage and increase in stability, a partial authority flight control system (hereinafter referred to as “PAFCS”) exists.
Since the control stick and the steering mechanism are mechanically connected in the PAFCS system, it is not necessary to compose a redundant system for providing high reliability to a control system, unlike the FBW system. In the PAFCS system, however, the operating range (authority) of the SAS actuator is restricted so as to enable manipulation by a pilot even when the control system is abnormal.
As an example of the PAFCS system, Japanese Patent No. 3195918 describes a flight control apparatus for helicopter configured with: a link mechanism for mechanically transmitting a manipulation amount for a manipulation section to a steering mechanism to drive the steering mechanism, a flight control law calculating section calculating a flight control law of a helicopter on the basis of a manipulation signal indicating detection of the manipulation amount for the manipulation section and outputting a steering mechanism driving signal, and a precision servo actuator section adding the amount of difference corresponding to a difference signal obtained by subtracting the manipulation signal from the driving signal, to the manipulation amount transmitted by the link mechanism.